<template>
    <div class="goods-image">
      
      <!-- 放大镜大图 -->
      <div v-if="images.length > 0" class="large" :style="[{backgroundImage:`url(${global.FILE_DOMAIN+images[currIndex]})`},bgPosition]" v-show="!isOutside"></div>

      <div v-if="goodsSkuImg" class="large" :style="[{backgroundImage:`url(${global.FILE_DOMAIN + goodsSkuImg})`},bgPosition]" v-show="!isOutside"></div>
        
      <!-- 左侧大图-->
      <div class="middle" ref="target">
          <!-- 显示商品SKU图片 -->
          <img v-if="goodsSkuImg" :src="global.FILE_DOMAIN + goodsSkuImg" alt="">
          <img v-else :src="global.FILE_DOMAIN + images[currIndex]" alt="">
          
          <!-- 蒙层小滑块 -->
          <div class="layer" v-show="!isOutside" :style="position"></div>
      </div>

      <!-- 小图列表 -->
      <ul class="small">
          <li v-for="(img,i) in images" :key="img" :class="{active:i===currIndex}">
              <img @mouseenter="handleMouseenter(i)" :src="global.FILE_DOMAIN+img" alt="">
          </li>
      </ul>
    </div>
  </template>

<script setup>
import { ref, reactive, watch, inject } from 'vue'
import { useMouseInElement } from '@vueuse/core'

// 获取全局对象
const global = inject('global')

defineProps({
  images: {
    type: Array,
    default: []
  },
  goodsSkuImg: {
    type: String,
    default: ''
  }
})

const emit = defineEmits(['setGoodsSkuImg'])

const currIndex = ref(0)
const target = ref(null)
// elementX 鼠标基于容器左上角X轴偏移
// elementY 鼠标基于容器左上角Y轴偏移
// isOutside 鼠标是否在模板容器外
const { elementX, elementY, isOutside } = useMouseInElement(target)
const position = reactive({ left: 0, top: 0 })
const bgPosition = reactive({ backgroundPositionX: 0, backgroundPositionY: 0 })
watch([elementX, elementY, isOutside], () => {
  // 如果鼠标移入到盒子里面才执行一下逻辑
  if (!isOutside.value) {
    // 控制X轴方向的定位 0-200 之间
    if (elementX.value < 100) position.left = 0
    else if (elementX.value > 300) position.left = 200
    else position.left = elementX.value - 100
    // 控制Y轴方向的定位 0-200 之间
    if (elementY.value < 100) position.top = 0
    else if (elementY.value > 300) position.top = 200
    else position.top = elementY.value - 100
    // 设置大背景的定位
    bgPosition.backgroundPositionX = -position.left * 2 + 'px'
    bgPosition.backgroundPositionY = -position.top * 2 + 'px'
    // 设置遮罩容器的定位
    position.left = position.left + 'px'
    position.top = position.top + 'px'
  }
})

const handleMouseenter = (i) => {
  currIndex.value = i
  emit('setGoodsSkuImg')
}
</script>

<style scoped lang="scss">
  .goods-image {
    width: 480px;
    height: 400px;
    position: relative;
    display: flex;
    z-index: 99;
    .large {
      position: absolute;
      top: 0;
      left: 412px;
      width: 400px;
      height: 400px;
      box-shadow: 0 0 10px rgba(0,0,0,0.1);
      background-repeat: no-repeat;
      background-size: 800px 800px;
      background-color: #f8f8f8;
    }
    .middle {
      width: 400px;
      height: 400px;
      background: #f5f5f5;
      position: relative;
      border: 1px solid #ccc;
      cursor: move;
      .layer {
        width: 200px;
        height: 200px;
        background: rgba(0,0,0,.2);
        left: 0;
        top: 0;
        position: absolute;
      }
      img {
        height: 100%;
        width: 100%;
      }
    }
    .small {
      width: 80px;
      li {
        width: 68px;
        height: 68px;
        margin-left: 12px;
        margin-bottom: 15px;
        cursor: pointer;
        img {
          width: 100%;
          height: 100%;
        }
        &:hover,&.active {
          border: 2px solid $main-color;
        }
      }
    }
  }
</style>